The overall goal of the Critical Path Project (CPP; Project 1) is to coordinate cGMP- compliant Drug Substance and Drug Product manufacture and release, manage preclinical safety and efficacy studies, and develop and integrate regulatory documents for submission of an Investigational New Drug (IND) application to US Food and Drug Administration (FDA), in support of an investigative clinical trial. Project 1 will establish the manufacturing methodology for the new product and help define an accelerated development path towards demonstration of clinical efficacy and product licensure. The novel active pharmaceutical ingredient (API) of our microbicide is Griffithsin (GRFT), a marine algal natural protein for which we have developed and scaled an efficient recombinant manufacturing process. GRFT is the most potent HIV-1 entry inhibitor known and also has high activity against other viruses that may be co-transmitted with HIV, such as HSV-2. Through our collaborators in the PREVENT Program, we have produced more than 200 g of GRFT for research use, and developed effective and stable microbicide gel dosage forms. These prototype gels have been evaluated for initial safety in an ex vivo human explant system, physicochemical stability and API release characteristics with very encouraging results. In Aim 1 of this Project, we will apply methods we have successfully used to date to further optimize the API manufacturing process for maximum yield and recovery. The manufacturing process will be brought to compliance with FDA cGMP guidelines, together with supporting documentation. Compliant API will be used to cGMP manufacture the rectal gel final dosage form optimized in Core B. In Aim 2, the safety and tolerability of the rectal gel product will be determined in regulation-compliant toxicology in 3 animal species, with endpoints to include topical and systemic safety, tolerability, irritation, sensitivity and immunotoxicity. Preliminary Chemistry, Manufacturing and Controls (CMC) and safety information along with a draft clinical Protocol will be discussed with FDA in a pre-IND meeting. Agency feedback will assist us in finalizing an IND application, activation of which by FDA will allow us to initiate a first-in-humans clinical trial of the GRFT microbicide in Project 3.